A method for preparing an Al-Cu-Mg aluminum alloy thin-walled small-size extruded profile for aviation

Abstract

The application relates to a preparation method of an Al-Cu-Mg aluminum alloy thin-wall small-size extruded section for aviation, and relates to a preparation method of an Al-Cu-Mg aluminum alloy thin-wall small-size extruded section for aviation. The application is aimed at solving the technical problems of Al-Cu-Mg aluminum alloy thin-wall small-size section extrusion forming and solid solution process, and the method comprises the following steps: ingot homogenization annealing, ingot car, ingot heating, ingot extrusion, two-stage solid solution treatment, section stretching and natural aging. In the application, the tensile strength of the T3511 state section of the Al-Cu-Mg aluminum alloy thin-wall small-size extruded section for aviation can reach 436 MPa to 512 MPa, the yield strength can reach 329 MPa to 403 MPa, and the elongation after fracture is greater than 13.64% to 20.53%. The performance meets the product standard requirements, and the self-supporting capability of the domesticization of the aluminum alloy raw material for aviation is improved. The application is applied to the field of aluminum alloy extruded material processing technology.

Description

Technical Field

[0001] This invention relates to a method for preparing thin-walled, small-size extruded Al-Cu-Mg aluminum alloy profiles for aerospace applications. Background Technology

[0002] With the rapid development of the aviation industry and the proposal of the dual-carbon strategy of "carbon peaking" and "carbon neutrality," the aviation industry has higher requirements for reducing energy consumption and lightweighting, which also places stricter requirements on the aluminum alloy manufacturing industry. Aviation aluminum materials are also developing towards higher strength and better comprehensive performance. Al-Cu-Mg aluminum alloy extruded profiles are widely used due to their high strength and significant heat treatment strengthening effect. Some research has been carried out in China on small-size profiles for domestically produced large fire-fighting / water rescue amphibious aircraft. In order to meet the urgent need for the localization of key aluminum alloy materials for this type of aircraft, research on industrial preparation technology is needed to solve technical problems such as extrusion molding and solution treatment of thin-walled small-size Al-Cu-Mg aluminum alloy profiles, and improve the self-sufficiency of domestic aluminum alloy raw materials for aviation. Summary of the Invention

[0003] The present invention provides a method for preparing thin-walled, small-size extruded Al-Cu-Mg aluminum alloy profiles for aerospace applications.

[0004] The present invention discloses a method for preparing thin-walled, small-diameter extruded Al-Cu-Mg aluminum alloy profiles for aerospace applications, comprising the following steps:

[0005] 1. Heat the Al-Cu-Mg aluminum alloy ingot to 480℃~490℃ and hold for 6h~15h. After holding, remove it from the furnace and air cool it to obtain the homogenized Al-Cu-Mg aluminum alloy ingot.

[0006] 2. The homogenized Al-Cu-Mg aluminum alloy ingot obtained in step 1 is machined to obtain extruded ingot billet.

[0007] 3. Heat the Al-Cu-Mg aluminum alloy ingot obtained from step 2 to 410℃~430℃ for 5h~10h, and then extrude it using an extrusion die after it is taken out of the furnace.

[0008] 4. The Al-Cu-Mg aluminum alloy extruded profile obtained in step 3 is subjected to solution heat treatment. The temperature is held at 480℃~486℃ for 15min~35min, and then the temperature is raised to 490℃~496℃ and held for 35min~55min. The extruded profile is stretched within 4h, and the stretching amount is controlled at 1.5%~3.0% to obtain the Al-Cu-Mg aluminum alloy quenched and stretched profile.

[0009] 5. After quenching and stretching, the Al-Cu-Mg aluminum alloy profile obtained in step 4 is subjected to natural aging to obtain the Al-Cu-Mg aluminum alloy T3511 state profile.

[0010] Beneficial effects of this invention:

[0011] 1. This invention develops a method for preparing thin-walled, small-specification extruded Al-Cu-Mg aluminum alloy profiles for aviation applications. A special extrusion die is designed for profile extrusion, solving the problems of difficulty in controlling the wall thickness and external dimensions of small-walled profiles, and ensuring that the final product meets the standard requirements.

[0012] 2. This invention develops a method for preparing thin-walled, small-diameter extruded Al-Cu-Mg aluminum alloy profiles for aerospace applications. It employs a two-stage solution treatment method. The first stage of solution treatment is performed at a relatively low temperature to release more deformation energy, reduce the recrystallization driving force of the high-temperature solution treatment, and improve alloy performance. A second stage of high-temperature solution treatment is then performed to improve the dissolution effect of the second phase. The average tensile strength in the T3511 state reaches 468 MPa, exceeding the product standard requirement by 92 MPa, and the average yield strength reaches 356 MPa, exceeding the product standard requirement by 66 MPa. This method addresses the demand for high-strength aluminum alloy materials in key aircraft models, meets the airworthiness certification requirements for key aircraft materials, and can be widely applied in my country's aerospace field, achieving the urgent goal of import substitution and realizing domestic self-sufficiency.

[0013] This invention is applicable to the preparation of thin-walled, small-size extruded profiles of Al-Cu-Mg aluminum alloy. Attached Figure Description

[0014] Figure 1 This is a cross-sectional view of the profile.

[0015] Figure 2 This refers to the profile-specific mold used in the embodiments;

[0016] Figure 3 In this embodiment, a special mold is used to extrude the actual profile.

[0017] Figure 4 The metallographic structure of the head and tail positions of the thin-walled small-size extruded Al-Cu-Mg aluminum alloy profile for aerospace prepared as an example. Detailed Implementation

[0018] Specific Implementation Method 1: This implementation method describes a method for preparing thin-walled, small-diameter extruded Al-Cu-Mg aluminum alloy profiles for aerospace applications, which is carried out according to the following steps:

[0019] 1. Heat the Al-Cu-Mg aluminum alloy ingot to 480℃~490℃ and hold for 6h~15h. After holding, remove it from the furnace and air cool it to obtain the homogenized Al-Cu-Mg aluminum alloy ingot.

[0020] 2. The homogenized Al-Cu-Mg aluminum alloy ingot obtained in step 1 is machined to obtain extruded ingot billet.

[0021] 3. Heat the Al-Cu-Mg aluminum alloy ingot obtained from step 2 to 410℃~430℃ for 5h~10h, and then extrude it using an extrusion die after it is taken out of the furnace.

[0022] 4. The Al-Cu-Mg aluminum alloy extruded profile obtained in step 3 is subjected to solution heat treatment. The temperature is held at 480℃~486℃ for 15min~35min, and then the temperature is raised to 490℃~496℃ and held for 35min~55min. The extruded profile is stretched within 4h, and the stretching amount is controlled at 1.5%~3.0% to obtain the Al-Cu-Mg aluminum alloy quenched and stretched profile.

[0023] 5. After quenching and stretching, the Al-Cu-Mg aluminum alloy profile obtained in step 4 is subjected to natural aging to obtain the Al-Cu-Mg aluminum alloy T3511 state profile.

[0024] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that: in step one, the temperature is raised to 485°C and maintained for 8 hours. Everything else is the same as in Specific Implementation Method One.

[0025] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that: in step three, the temperature is raised to 420℃~430℃ for 6 hours. Everything else is the same as in Specific Implementation Method One or Two.

[0026] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the extrusion die described in step three is an alloy cylinder with a T-shaped through hole. Everything else is the same as in Specific Implementation Methods One to Three.

[0027] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that: in step three, a forward extrusion method is used for extrusion. Everything else is the same as in Specific Implementation Methods One to Four.

[0028] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that: in step four, the temperature is maintained at 483°C for 20 minutes, and then raised to 496°C and maintained for 51 minutes. Everything else is the same as in Specific Implementation Methods One to Five.

[0029] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that: in step four, the stretching is performed within 4 hours, and the stretching amount is controlled between 2.0% and 2.5%. Everything else is the same as in Specific Implementation Methods One to Six.

[0030] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that the natural aging time in Step Five refers to natural parking for 96 hours. Everything else is the same as in Specific Implementation Methods One to Seven.

[0031] The scope of this invention is not limited to the above-described embodiments; a combination of one or more specific embodiments can also achieve the purpose of the invention.

[0032] Example 1: This example describes a method for preparing a thin-walled, small-diameter extruded Al-Cu-Mg aluminum alloy profile for aerospace applications, which is carried out according to the following steps:

[0033] 1. Heat the Al-Cu-Mg aluminum alloy ingot to 485℃ and hold for 8 hours. After holding, remove it from the furnace and air cool it to obtain the homogenized Al-Cu-Mg aluminum alloy ingot.

[0034] 2. The homogenized Al-Cu-Mg aluminum alloy ingot obtained in step 1 is machined to obtain an extruded ingot billet with a specification of φ80mm×240mm.

[0035] 3. Heat the Al-Cu-Mg aluminum alloy ingot obtained from step 2 to 420℃~430℃ for 6 hours. After removing it from the furnace, use a self-designed extrusion die (such as...) Figure 2 (As shown) is extruded using a forward extrusion method;

[0036] 4. The Al-Cu-Mg aluminum alloy extruded profile obtained in step 3 is subjected to solution heat treatment. The temperature is held at 483℃ for 20 minutes, then raised to 496℃ and held for 51 minutes. The extruded profile is stretched within 4 hours, with the stretching amount controlled at 2.0% to 2.5%, to obtain the Al-Cu-Mg aluminum alloy quenched and stretched profile.

[0037] 5. After quenching and stretching, the Al-Cu-Mg aluminum alloy profile obtained in step 4 is subjected to natural aging and left to stand naturally for more than 96 hours to obtain the Al-Cu-Mg aluminum alloy T3511 state profile.

[0038] The aerospace-grade Al-Cu-Mg aluminum alloy thin-walled small-diameter extruded profile obtained in this embodiment (profile cross-section diagram as shown) Figure 1 As shown, the actual profile is as follows Figure 3 As shown), Figure 4 The metallographic structure of the extruded profile at the head and tail positions is determined by... Figure 4It can be seen that only a small amount of S and Fe phases exist in the metallographic structure, the overall solid solution effect is good, and the structure at both ends is relatively uniform. The tensile strength of the Al-Cu-Mg aluminum alloy thin-walled small-size extruded profiles for aerospace applications can reach 436MPa~512MPa, the yield strength can reach 329MPa~403MPa, and the elongation after fracture is greater than 13.64%~20.53%.

Claims

1. A method for preparing thin-walled, small-diameter extruded Al-Cu-Mg aluminum alloy profiles for aerospace applications, characterized in that... This method is performed in the following steps:

1. Heat the Al-Cu-Mg aluminum alloy ingot to 485℃ and hold for 8 hours. After holding, remove it from the furnace and air cool it to obtain the homogenized Al-Cu-Mg aluminum alloy ingot.

2. The homogenized Al-Cu-Mg aluminum alloy ingot obtained in step 1 is machined to obtain extruded ingot billet.

3. Heat the Al-Cu-Mg aluminum alloy ingot obtained in step 2 to 410℃~430℃ for 5h~10h, and then extrude it using an extrusion die after it comes out of the furnace; the extrusion die is an alloy cylinder with a T-shaped through hole.

4. The Al-Cu-Mg aluminum alloy extruded profile obtained in step 3 is subjected to solution heat treatment. The temperature is held at 483℃ for 20 minutes, then raised to 496℃ and held for 51 minutes. The extrusion is then stretched within 4 hours, with the stretching amount controlled at 1.5%~3.0%, to obtain the Al-Cu-Mg aluminum alloy quenched and stretched profile.

5. After quenching and stretching, the Al-Cu-Mg aluminum alloy profile obtained in step 4 is subjected to natural aging to obtain the Al-Cu-Mg aluminum alloy T3511 state profile.

2. The method for preparing a thin-walled, small-diameter extruded Al-Cu-Mg aluminum alloy profile for aerospace applications according to claim 1, characterized in that, In step three, heat to 420℃~430℃ for 6 hours.

3. The method for preparing a thin-walled, small-diameter extruded Al-Cu-Mg aluminum alloy profile for aerospace applications according to claim 1, characterized in that, In step three, a forward extrusion method is used for extrusion.

4. The method for preparing a thin-walled, small-diameter extruded Al-Cu-Mg aluminum alloy profile for aerospace applications according to claim 1, characterized in that, Step four involves stretching the material within 4 hours, with the stretching amount controlled between 2.0% and 2.5%.

5. The method for preparing a thin-walled, small-diameter extruded Al-Cu-Mg aluminum alloy profile for aerospace applications according to claim 1, characterized in that, The natural aging period in step five refers to 96 hours of natural parking.

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